kernel recognizing large (> 2.1 TB) block devices ?

[Peter Arremann]

On Tuesday 04 January 2005 21:14, Randall A. Jones wrote:
> I have a 4.8TB RAID device attached to a FC3 system via SCSI.
> The system recognizes a RAID LUN volume of 2.1TB or less without any
> problem.  When I configure the RAID as a full 4.8TB LUN, the kernel
> fails to recognize its actual size and gives the following message on
> boot and initialization of the aic7xxx driver:
> --
> scsi1 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 6.2.36
>         <Adaptec 3960D Ultra160 SCSI adapter>
>         aic7899: Ultra160 Wide Channel A, SCSI Id=7, 32/253 SCBs
>
> scsi1:A:4:0: DV failed to configure device.  Please file a bug report
> against th
> is driver.
> (scsi1:A:4): 80.000MB/s transfers (40.000MHz, offset 24, 16bit)
>   Vendor: NEXSAN    Model: ATAboy(C0A82A0F)  Rev: 4032
>   Type:   Direct-Access                      ANSI SCSI revision: 04
> scsi1:A:4:0: Tagged Queuing enabled.  Depth 4
> sdc : very big device. try to use READ CAPACITY(16).
> sdc : READ CAPACITY(16) failed.
> sdc : status=0, message=00, host=5, driver=00
> sdc : use 0xffffffff as device size
> SCSI device sdc: 4294967296 512-byte hdwr sectors (2199023 MB)
> SCSI device sdc: drive cache: write back
> --
>
> Then the reported size of the drive is truncated to 2.1TB, see above.
>
> The system is a dual processor 3.0GHz Xeon server running kernel
> 2.6.9-1.681_FC3smp.
> The system is a stock FC3 install with updates.
>
>
> In the kernel source, the config file, kernel-2.6.9-i686-smp.config,
> shows that LBD is in fact enabled.
> CONFIG_LBD=y
>
>
> Are there any other settings to enable the kernel to properly
> recognize a large block device?
>
> Any ideas or suggestions of things to try or check?

I doubt you will have any luck - standard scsi in itsself has a limit of 2TB 
(32bit block adressing with 512 byte blocks). LSI (others have followed 
since) has new enhancements 
(http://www.infortrend.com/%5CNews%5C20041006%5Cf_64Bit_LBA.htm) but I know 
of no storage devices that currently implement that since it is not an 
official standard and seems to have some other problems.... 

Your RAID should not allow you that or at least warn you if it supports the 
extension (what model is it?) but I know for sure that the adaptec 7xxx chips 
don't. You can try a LSI controller and see what happens or you can create 
multiple luns and then raid0 them - that should work for you snce you got 
LBD...

Peter.